Electric switch with locking means



Oct. 3, 1967 w. N. KEMNITZ 3,345,489

ELECTRIC SWIT CH WITH LOCKING MEANS Filed Sept. 7, 1965 38 INVENTOR.

' A K Hgjfl W RREN N EMNITZ 1 ATTORNEY United States Patent Ofiice 3,345,489 ELECTRIC SWITCH WITH LOCKING MEANS Warren N. Kemnitz, Racine, Wis., assignor to Scovill Manufacturing Company, Waterbury, Conn, a corporation of Connecticut Filed Sept. 7, 1965, Scr. No. 485,219 4 Claims. (Cl. 200-157) ABSTRACT OF THE DISCLOSURE An electric switch of the push button type comprising a housing having an opening therein and a switch button rotatably mounted in the opening, the housing including a button retaining stationary ring surrounding the opening and an inwardly radially extending web. The button has bearing means between the ring and the web retained by the ring and bearing on the web, and the web has recesses permitting depression of the button when the bearing means enter the recesses. The button is provided on its external face with means for rotating the button, and designations on the housing cooperating with the rotating means for indicating the locked or unlocked positions of the button. A contact member rotatable with the button engages fixed contacts in the housing when the button has been manually depressed.

This invention relates to an electric switch with locking means, and more particularly to an electric switch of the push button type provided with means for preventing accidental or unintentional actuation of the switch button.

As shown herein, the switch is embodied in an electric knife provided with reciprocated blades controlled by the switch. However, my electric switch with locking means may be made a part of other appliances or tools where it is desirable to prevent unintended operation of rotary or reciprocating parts.

The main object of the invention is to provide an electric switch comprising a switch actuating button accessible externally of a tool or appliance housing, normally retained in a locked, non-depressible position, and manual ly rotatable to an On position wherein the button is depressible for the purpose of closing an electrical switch.

Another object of the invention is to provide a switch having a switch actuating button accessible externally of a tool or appliance housing and provided with a contact member located within the housing, said contact member being rotated with the button and so located relatively to a pair of fixed electrical contacts that contact between the said contact member and the pair of fixed electrical contacts is possible only when'the button has been rotated manually from locked to On position and then depressed relatively to the housing.

In the drawings: v

FIG. 1 is a top plan view of the forward end of an electric knife embodying the electric switch with locking means of my invention, the knife handle housing and reciprocated blades being partly broken away.

FIG. 2 is a transverse vertical sectional view, on an enlarged scale, in the plane of the line 22 of FIG. 1.

FIG. 3 is a horizontal sectional view in the plane of the line 33 of FIG. 2.

FIG. 4 is a horizontal sectional view in the plane of the line 44 of FIG. 2.

In the embodiment shown herein, the invention is part of an electric knife having a housing with upwardly and inwardly inclined side walls 11 merging into a top 12. Reciprocated blades 13, provided with guards 14, are mounted in the knife housing 10 by tangs 15. The blades 13 are reciprocated by a motor (not shown) in the hous- 3,345,489 Patented Oct. 3, 1967 ing 10 controlled by the switch indicated as a whole at 20. As stated, the housing 10 may be the casing of a tool or appliance other than an electric knife, in which the switch 20 may be mounted.

The housing top 12 is provided with an opening defined by the circular ring or raised portion 21 which rises from the flat upper surfaces 22 of the walls 11. Beneath the opening in the top 12, the housing walls 11 are connected by a horizontal web 23 integral with a bearing 24 provided with a central bore. The bearing 24 extends both upwardly and downwardly from the web 23, the upwardly extending portion being spaced horizontally from the outer walls 11 to provide a concentric recess 25 between them.

The switch 20 comprises a button 26 which has a rib 27 extending across its top. The button 26 has a concentric side surface 28 which fits rotatably within the ring 21. The button 26 is provided with a pair of oppositely located ears 29 which extend radially from the side surface 28 adjacent its lower edge so that the ears 29 are located under the ring 21 and thus the button 26 is preventer from moving out of the opening in the housing top 12. The button 26 has a shank 30 which fits within the centrally bored bearing 24 for both rotatable and axial movement therein. A contact member 31 is fixedly connected to the lower end of the shank 30 by screw 32. A coiled spring 33 surrounds the shank 30 of the button in the recess 25, opposite ends of the spring bearing on the under side of the button 26 and on the upper surface of the web 23.

The contact member 31 is a flat metal bar bent between its ends to form a central apertured attaching portion 34 and opposite end contact surfaces 35, 36, the latter being located to contact fixed spaced contacts 37, 38, respectively, when the button has been rotated to On position and then depressed. The contacts 37, 38 are mounted on an insulating support 39 in the housing 10.

The operation of the switch is as follows: When the knife or other device is not in use, the button 26 is in the position shown in FIG. 1, where the rib 27 extends longitudinally of the housing 10, in alignment with the dot adjacent the designation Lock on the housing, The cars 29 on the button extend radially in a direction at right angles to the rib 27, and bear on the surface 40 of the housing walls 11, so that the button cannot be depressed. In this position of the button, the contact plate 31 extends at a 30 degree angle relatively to a vertical plane coincident with the rib 27, and thus the contact surfaces 35, 36, of the member 31 are out of register with the fixed contacts 37, 38, respectively. When the operator desires to use the knife and to actuate the switch, it is necessary to manually rotate the button 26 thirty degrees, turning the rib 27 to point toward the dot adjacent the designation On (FIG. 1). This rotation of the button results in moving the ears 29 into register with recesses 41 in the wall surface 40, thus permitting the button to be depressed through the ear receiving recesses '41 into the concentric recess 25, thereby compressing the spring 33. Rotation of the button also has turned the shank and the contact member 31 attached to the shank, so that contact surfaces 35, 36 are located in register with the fixed contacts 37, 38, respectively, and make contact therewith when the button is depressed.

It will be understood that the cars 29, 29 extend in a direction at right angles to the rib 27, and that the contact member 31 is fixed on the button shank 30 to extend at an angle approximately 30 degrees from the radial direction of the ears and from a line extending through the centers of the fixed contacts 37, 38. Thus rotation of the button 26 to turn the rib 27 from Lock to On, through an arc of about 30 degrees, moves the cars 29 and the contact surfaces 35, 36 accordingly, thereby permitting depression of the button and closing of the switch contacts by contact of the surfaces 35, 36, with the contacts 37, 38 respectively. c

When pressure is removed from the button 26, the spring 33 automatically returns the button to non-depressed position, Where it can be rotated by the user to the Lock position in which the button is non-depressible.

1 Changes may be made in the form and arrangement of parts without departing from the scope of the invention as defined by the appended claims.

I claim:

1. An electric switch of the push button type provided with locking means for preventing unintentional depression and actuation of the switch button, comprising (a) a housing provided with an opening therein surrounded by a button retaining stationary ring, an inwardly radially extending web forming a bearing surface in the housing,

(b) a switch button rotatably mounted in the housing 7 opening and provided on its external face with means for manually rotating the button to depressible or locked, undepressible positions,

() designations on the housing adjacent the opening cooperating with the manually rotating means which indicate the depressible and locked positions of the button, 7

(d) bearing means on the button contacted by the re taining ring and engaging the bearing surface on the web for preventing depression of the button when in locked position,

(e) the said bearing surface having a recess therein for receiving said bearing means on the button and permitting depression of the button when rotated to unlocked position,

(f) a pair of fixed contacts mounted in the housing,

and

(g) a contact member mounted on the button Within the housing and rotatable with the button to engage the fixed contacts when the button has been rotated to unlocked position and depressed.

2. The electric switch defined by claim 1, in which the bearing means on the button are radially extending oppositely located ears on the button.

3. An electric switch of the push button type provided with locking means for preventing unintentional depression and actuation of the switch button, comprising (a) a housing provided with an opening therein surrounded by a button retaining stationary ring, an inwardly radially extending web forming a bearing surface in the housing,

(b) a switch button rotatably mounted in the housing opening and provided on its external face with a rib for manually rotating the button to a depressible position or to a locked, undepressible position,

(c) designations on the housing adjacent the opening cooperating with the rig which indicate the respective positions of the button,

(d) radially projecting ears oppositely located on the b t on side surface between the ring and Web for 4 engaging the bearing surface on the web for preventing depression of the button when in locked position,

(e) the said bearing surface having recesses therein for receiving said radially projecting ears and permitting depression of the button when rotated to unlocked position,

(f) a pair of fixed contacts mounted in the housing,

(g) a shank depending from the button,

(h) a coiled spring surrounding the shank between the housing and button, and

(i) a contact member mounted on the shank and rotatable with the button to engage th fixed contacts when the button has been rotated to unlocked position and depressed.

4. An electric switch of the push button type provided with locking means for preventing unintentional depression and actuation of the switch button, comprising (a) an electric knife handle housing provided with an opening therein surrounded by a button retaining stationary ring, an inwardly radially extending web forming a bearing surface in the housing,

(b) a switch button rotatably mounted in the housing opening and provided on its external face with a rib extending across the face for manually rotating the button to an unlocked depressible position or to a locked undepressible position,

(0) designations on the housing adjacent the opening which indicate the position of the button when the rib points to a selected one of the designations,

(d) radially projecting ears oppositely located on the button side surface between the ring and web for engaging the bearing surface on the web for preventing depression of the button when in locked position, said ears extending in a radial direction at right angles to the rib on the face of the button,

(e) the said bearing surface having recesses therein for receiving said radially projecting ears and permitting depression of the button when rotated to unlocked position,

(f) a pair of fixed contacts mounted in the housing,

said contacts being located in a line extending transversely of the knife handle housing parallel to the radial direction of the ears on the button,

(g) a shank depending from the button,

(h) a coiled spring surrounding the shank between the housing and button, and

(i) a contact member mounted on the shank and rotatable with the button to engage the fixed contacts when the button has been rotated to unlocked position and depressed.

References Cited UNITED STATES PATENTS 1,400,470 12/ 1931 Welch. 1,889,175 11/1932 Evans 200159 2,668,893 2/1954 Vaughan 200-159 ROBERT K. SCHAEFER, Primary Examiner,

BU KS, A i an x miner, 

1. AN ELECTRIC SWITCH OF THE PUSH BUTTON TYPE PROVIDED WITH LOCKING MEANS FOR PREVENTING UNINTENTIONAL DEPRESSION AND ACTUATION OF THE SWITCH BUTTON, COMPRISING (A) A HOUSING PROVIDED WITH AN OPENING THEREIN SURROUNDED BY A BUTTON RETAINING STATIONARY RING, AN INWARDLY RADIALLY EXTENDING WEB FORMING A BEARING SURFACE IN THE HOUSING, (B) A SWITCH BUTTON ROTATABLY MOUNTED IN THE HOUSING OPENING AND PROVIDED ON ITS EXTERNAL FACE WITH MEANS FOR MANUALLY ROTATING THE BUTTON TO DEPRESSIBLE OR LOCKED, UNDEPRESSIBLE POSITONS, (C) DESIGNATIONS ON THE HOUSING ADJACENT THE OPENING COOPERATING WITH THE MANUALLY ROTATING MEANS WHICH INDICATE THE DEPRESSIBLE AND LOCKED POSITIONS OF THE BUTTON, (D) BEARING MEANS ON THE BUTTON CONTACTED BY THE RETAINING RING AND ENGAGING THE BEARING SURFACE ON THE WEB FOR PREVENTING DEPRESSION OF THE BUTTON WHEN IN LOCKED POSITION, (E) THE SAID BEARING SURFACE HAVING A RECESS THEREIN FOR RECEIVING SAID BEARING MEANS ON THE BUTTON AND PERMITTING DEPRESSION OF THE BUTTON WHEN ROTATED TO UNLOCKED POSITION, (F) A PAIR OF FIXED CONTACTS MOUNTED IN THE HOUSING, AND (G) A CONTACT MEMBER MOUNTED ON THE BUTTON WITHIN THE HOUSING AND ROTATABLE WITH THE BUTTON TO ENGAGE THE FIXED CONTACTS WHEN THE BUTTON HAS BEEN ROTATED TO UNLOCKED POSITION AND DEPRESSED. 